No.8.] COPE ON EOCENE VERTEBEATA OF WIND RIVER. ISO- 



allied Species, this tooth is rather longer, evidently in consequence of a 

 well-developed heel. The fourth premolar has a strong inner tubercle, 

 and no anterior cusp or cingulum. Its heel has an elevated posterior 

 border, enclosing a fossa with the principal cusps. No external or inter- 

 nal cingula. Third premolar with two roots. Alveolus of the second, 

 large and apparently simple ; it is filled with matrix. Canine large, 

 directed forwards, and occupying all the space between a short dias- 

 tema and the symphysis. The latter extends posteriorly to below the 

 anterior part of the third premolar. The ramus is compressed and 

 maintains an equal depth to the end of the molar series. Its inferior 

 border descends below the coronoid process, and is not incurved, but 

 the external face is convex. The anterior masseteric ridge is well 

 marked, descending to below the middle of the ramus. Masseteric 

 fossa flat. Mental foramen below the third premolar. 



Measuretnents. 



M. 



Length of the fragment of ramus 0435 



Length of dental series without incisors 0280 



c antero-posterior 0040 



Diameters of canine j^^^^^^^^g^ _ ^^^^ 



Length of premolar series 0100 



Length of fourth premolar 0040 



Width of fourth premolar behind 0027 



Length of true molar series 0136 



Length of last true molar 0052 



Width of last true molar anteriorly 0030 



Depth of ramus at third premolar 0090 



Depth of ramus at last molar 0090 



This species is dedicated to my friend Prof. William B. Scott, of the 

 College of New Jersey. 



CREODONTA. 



22. MlACIS CANAVUS sp. nov. 



Established on the mandibular rami of two individuals, which display 

 the roots and some of the crowns of all the teeth exclusive of the in- 

 cisors. 



The root of the canine indicates that the crown is of large size and 

 compressed at the base. The first premolar is one-rooted, and is sepa- 

 rated from the second by a short diastema. The second has two well- 

 distinguished roots, which are separated from those of the third by a dias- 

 tema like that in front of them. Posterior to this there are no diastemata. 

 The second root of the fourth premolar is much larger than the anterior. 

 The sectorial, though the largest tooth, is of but moderate dimensions; 

 its heel supports two posterior tubercles. The first tubercular is a lit- 

 tle shorter. It has a raised border, and the anterior j^art two angu- 

 lar tubercles. The second tubercular is a very small tooth, but has two 

 roots, the posterior of which is posterior to the anterior border of the 

 ascending ramus. 



